/*
- * hvc_iucv.c - z/VM IUCV back-end for the Hypervisor Console (HVC)
+ * hvc_iucv.c - z/VM IUCV hypervisor console (HVC) device driver
*
- * This back-end for HVC provides terminal access via
+ * This HVC device driver provides terminal access using
* z/VM IUCV communication paths.
*
- * Copyright IBM Corp. 2008.
+ * Copyright IBM Corp. 2008
*
* Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
*/
#define KMSG_COMPONENT "hvc_iucv"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/types.h>
#include <asm/ebcdic.h>
#include "hvc_console.h"
-/* HVC backend for z/VM IUCV */
+/* General device driver settings */
#define HVC_IUCV_MAGIC 0xc9e4c3e5
#define MAX_HVC_IUCV_LINES HVC_ALLOC_TTY_ADAPTERS
#define MEMPOOL_MIN_NR (PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4)
#define MSG_TYPE_WINSIZE 0x08 /* Terminal window size update */
#define MSG_TYPE_DATA 0x10 /* Terminal data */
-#define MSG_SIZE(s) ((s) + offsetof(struct iucv_tty_msg, data))
struct iucv_tty_msg {
u8 version; /* Message version */
u8 type; /* Message type */
u16 datalen; /* Payload length */
u8 data[]; /* Payload buffer */
} __attribute__((packed));
+#define MSG_SIZE(s) ((s) + offsetof(struct iucv_tty_msg, data))
enum iucv_state_t {
IUCV_DISCONN = 0,
};
struct hvc_iucv_private {
- struct hvc_struct *hvc; /* HVC console struct reference */
+ struct hvc_struct *hvc; /* HVC struct reference */
u8 srv_name[8]; /* IUCV service name (ebcdic) */
enum iucv_state_t iucv_state; /* IUCV connection status */
enum tty_state_t tty_state; /* TTY status */
struct iucv_tty_buffer {
struct list_head list; /* list pointer */
- struct iucv_message msg; /* store an incoming IUCV message */
+ struct iucv_message msg; /* store an IUCV message */
size_t offset; /* data buffer offset */
struct iucv_tty_msg *mbuf; /* buffer to store input/output data */
};
}
/**
- * alloc_tty_buffer() - Returns a new struct iucv_tty_buffer element.
+ * alloc_tty_buffer() - Return a new struct iucv_tty_buffer element.
* @size: Size of the internal buffer used to store data.
* @flags: Memory allocation flags passed to mempool.
*
* allocates an internal data buffer with the specified size @size.
* Note: The total message size arises from the internal buffer size and the
* members of the iucv_tty_msg structure.
- *
* The function returns NULL if memory allocation has failed.
*/
static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
/**
* destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
* @bufp: Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
- *
- * The destroy_tty_buffer() function frees the internal data buffer and returns
- * the struct iucv_tty_buffer element back to the mempool for freeing.
*/
static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
{
/**
* destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
- * @list: List head pointer to a list containing struct iucv_tty_buffer
- * elements.
- *
- * Calls destroy_tty_buffer() for each struct iucv_tty_buffer element in the
- * list @list.
+ * @list: List containing struct iucv_tty_buffer elements.
*/
static void destroy_tty_buffer_list(struct list_head *list)
{
}
/**
- * hvc_iucv_write() - Receive IUCV message write data to HVC console buffer.
- * @priv: Pointer to hvc_iucv_private structure.
- * @buf: HVC console buffer for writing received terminal data.
- * @count: HVC console buffer size.
+ * hvc_iucv_write() - Receive IUCV message & write data to HVC buffer.
+ * @priv: Pointer to struct hvc_iucv_private
+ * @buf: HVC buffer for writing received terminal data.
+ * @count: HVC buffer size.
* @has_more_data: Pointer to an int variable.
*
* The function picks up pending messages from the input queue and receives
* the message data that is then written to the specified buffer @buf.
- * If the buffer size @count is less than the data message size, then the
+ * If the buffer size @count is less than the data message size, the
* message is kept on the input queue and @has_more_data is set to 1.
- * If the message data has been entirely written, the message is removed from
+ * If all message data has been written, the message is removed from
* the input queue.
*
* The function returns the number of bytes written to the terminal, zero if
* there are no pending data messages available or if there is no established
* IUCV path.
* If the IUCV path has been severed, then -EPIPE is returned to cause a
- * hang up (that is issued by the HVC console layer).
+ * hang up (that is issued by the HVC layer).
*/
static int hvc_iucv_write(struct hvc_iucv_private *priv,
char *buf, int count, int *has_more_data)
int written;
int rc;
- /* Immediately return if there is no IUCV connection */
+ /* immediately return if there is no IUCV connection */
if (priv->iucv_state == IUCV_DISCONN)
return 0;
- /* If the IUCV path has been severed, return -EPIPE to inform the
- * hvc console layer to hang up the tty device. */
+ /* if the IUCV path has been severed, return -EPIPE to inform the
+ * HVC layer to hang up the tty device. */
if (priv->iucv_state == IUCV_SEVERED)
return -EPIPE;
if (list_empty(&priv->tty_inqueue))
return 0;
- /* receive a iucv message and flip data to the tty (ldisc) */
+ /* receive an iucv message and flip data to the tty (ldisc) */
rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
written = 0;
case MSG_TYPE_WINSIZE:
if (rb->mbuf->datalen != sizeof(struct winsize))
break;
- hvc_resize(priv->hvc, *((struct winsize *)rb->mbuf->data));
+ hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data));
break;
case MSG_TYPE_ERROR: /* ignored ... */
* @buf: Pointer to a buffer to store data
* @count: Size of buffer available for writing
*
- * The hvc_console thread calls this method to read characters from
- * the terminal backend. If an IUCV communication path has been established,
- * pending IUCV messages are received and data is copied into buffer @buf
- * up to @count bytes.
+ * The HVC thread calls this method to read characters from the back-end.
+ * If an IUCV communication path has been established, pending IUCV messages
+ * are received and data is copied into buffer @buf up to @count bytes.
*
* Locking: The routine gets called under an irqsave() spinlock; and
* the routine locks the struct hvc_iucv_private->lock to call
* @count: Size of buffer and amount of data to send.
*
* The function queues data for sending. To actually send the buffered data,
- * a work queue function is * scheduled (with QUEUE_SNDBUF_DELAY).
+ * a work queue function is scheduled (with QUEUE_SNDBUF_DELAY).
* The function returns the number of data bytes that has been buffered.
*
* If the device is not connected, data is ignored and the function returns
* @count.
* If the buffer is full, the function returns 0.
- * If an existing IUCV communicaton path has been severed, the function returns
- * -EPIPE (can be passed to HVC layer to cause a tty hangup).
+ * If an existing IUCV communicaton path has been severed, -EPIPE is returned
+ * (that can be passed to HVC layer to cause a tty hangup).
*/
static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf,
- int count)
+ int count)
{
size_t len;
* hvc_iucv_send() - Send an IUCV message containing terminal data.
* @priv: Pointer to struct hvc_iucv_private instance.
*
- * If an IUCV communication path has been established, the queued data
- * for output are sent via an IUCV message.
- *
- * If there is no IUCV communication path established, the function returns 0.
- * If an existing IUCV communicaton path has been severed, the function returns
- * -EPIPE.
+ * If an IUCV communication path has been established, the buffered output data
+ * is sent via an IUCV message and the number of bytes sent is returned.
+ * Returns 0 if there is no established IUCV communication path or
+ * -EPIPE if an existing IUCV communicaton path has been severed.
*/
static int hvc_iucv_send(struct hvc_iucv_private *priv)
{
* hvc_iucv_sndbuf_work() - Send buffered data over IUCV
* @work: Work structure.
*
- * The function sends buffered output data over IUCV and, if necessary,
- * reschedules itself if not all buffered data could be sent.
+ * This work queue function sends buffered output data over IUCV and,
+ * if not all buffered data could be sent, reschedules itself.
*/
static void hvc_iucv_sndbuf_work(struct work_struct *work)
{
struct hvc_iucv_private *priv;
priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
-
if (!priv)
return;
* @buf: Pointer to an buffer to read data from
* @count: Size of buffer available for reading
*
- * The hvc_console thread calls this method to write characters from
- * to the terminal backend.
- * The function calls hvc_iucv_send() under the lock of the
- * struct hvc_iucv_private instance that corresponds to the tty @vtermno.
+ * The HVC thread calls this method to write characters to the back-end.
+ * The function calls hvc_iucv_queue() to queue terminal data for sending.
*
* Locking: The method gets called under an irqsave() spinlock; and
* locks struct hvc_iucv_private->lock.
}
/**
- * hvc_iucv_cleanup() - Clean up function if the tty portion is finally closed.
+ * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
* @priv: Pointer to the struct hvc_iucv_private instance.
- *
- * The functions severs the established IUCV communication path (if any), and
- * destroy struct iucv_tty_buffer elements from the in- and outqueue. Finally,
- * the functions resets the states to TTY_CLOSED and IUCV_DISCONN.
*/
static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
{
}
/**
- * hvc_iucv_notifier_hangup() - HVC notifier for tty hangups.
- * @hp: Pointer to the HVC device (struct hvc_struct)
- * @id: Additional data (originally passed to hvc_alloc): the index of an struct
- * hvc_iucv_private instance.
+ * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
+ * @hp: Pointer to the HVC device (struct hvc_struct)
+ * @id: Additional data (originally passed to hvc_alloc):
+ * the index of an struct hvc_iucv_private instance.
*
- * This routine notifies the HVC backend that a tty hangup (carrier loss,
+ * This routine notifies the HVC back-end that a tty hangup (carrier loss,
* virtual or otherwise) has occured.
- *
- * The HVC backend for z/VM IUCV ignores virtual hangups (vhangup()), to keep
- * an existing IUCV communication path established.
+ * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
+ * to keep an existing IUCV communication path established.
* (Background: vhangup() is called from user space (by getty or login) to
* disable writing to the tty by other applications).
- *
- * If the tty has been opened (e.g. getty) and an established IUCV path has been
- * severed (we caused the tty hangup in that case), then the functions invokes
- * hvc_iucv_cleanup() to clean up.
+ * If the tty has been opened and an established IUCV path has been severed
+ * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
*
* Locking: struct hvc_iucv_private->lock
*/
spin_lock_bh(&priv->lock);
/* NOTE: If the hangup was scheduled by ourself (from the iucv
- * path_servered callback [IUCV_SEVERED]), then we have to
- * finally clean up the tty backend structure and set state to
- * TTY_CLOSED.
- *
+ * path_servered callback [IUCV_SEVERED]), we have to clean up
+ * our structure and to set state to TTY_CLOSED.
* If the tty was hung up otherwise (e.g. vhangup()), then we
* ignore this hangup and keep an established IUCV path open...
* (...the reason is that we are not able to connect back to the
* @id: Additional data (originally passed to hvc_alloc):
* the index of an struct hvc_iucv_private instance.
*
- * This routine notifies the HVC backend that the last tty device file
- * descriptor has been closed.
- * The function calls hvc_iucv_cleanup() to clean up the struct hvc_iucv_private
- * instance.
+ * This routine notifies the HVC back-end that the last tty device fd has been
+ * closed. The function calls hvc_iucv_cleanup() to clean up the struct
+ * hvc_iucv_private instance.
*
* Locking: struct hvc_iucv_private->lock
*/
/**
* hvc_iucv_path_pending() - IUCV handler to process a connection request.
* @path: Pending path (struct iucv_path)
- * @ipvmid: Originator z/VM system identifier
+ * @ipvmid: z/VM system identifier of originator
* @ipuser: User specified data for this path
* (AF_IUCV: port/service name and originator port)
*
- * The function uses the @ipuser data to check to determine if the pending
- * path belongs to a terminal managed by this HVC backend.
- * If the check is successful, then an additional check is done to ensure
- * that a terminal cannot be accessed multiple times (only one connection
- * to a terminal is allowed). In that particular case, the pending path is
- * severed. If it is the first connection, the pending path is accepted and
- * associated to the struct hvc_iucv_private. The iucv state is updated to
- * reflect that a communication path has been established.
+ * The function uses the @ipuser data to determine if the pending path belongs
+ * to a terminal managed by this device driver.
+ * If the path belongs to this driver, ensure that the terminal is not accessed
+ * multiple times (only one connection to a terminal is allowed).
+ * If the terminal is not yet connected, the pending path is accepted and is
+ * associated to the appropriate struct hvc_iucv_private instance.
*
- * Returns 0 if the path belongs to a terminal managed by the this HVC backend;
+ * Returns 0 if @path belongs to a terminal managed by the this device driver;
* otherwise returns -ENODEV in order to dispatch this path to other handlers.
*
* Locking: struct hvc_iucv_private->lock
priv = hvc_iucv_table[i];
break;
}
-
if (!priv)
return -ENODEV;
* sets the iucv state to IUCV_SEVERED for the associated struct
* hvc_iucv_private instance. Later, the IUCV_SEVERED state triggers a tty
* hangup (hvc_iucv_get_chars() / hvc_iucv_write()).
- *
- * If tty portion of the HVC is closed then clean up the outqueue in addition.
+ * If tty portion of the HVC is closed, clean up the outqueue.
*
* Locking: struct hvc_iucv_private->lock
*/
* @path: Pending path (struct iucv_path)
* @msg: Pointer to the IUCV message
*
- * The function stores an incoming message on the input queue for later
+ * The function puts an incoming message on the input queue for later
* processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
- * However, if the tty has not yet been opened, the message is rejected.
+ * If the tty has not yet been opened, the message is rejected.
*
* Locking: struct hvc_iucv_private->lock
*/
return;
}
+
spin_lock(&priv->lock);
/* reject messages if tty has not yet been opened */
list_add_tail(&rb->list, &priv->tty_inqueue);
- hvc_kick(); /* wake up hvc console thread */
+ hvc_kick(); /* wake up hvc thread */
unlock_return:
spin_unlock(&priv->lock);
* @path: Pending path (struct iucv_path)
* @msg: Pointer to the IUCV message
*
- * The function is called upon completion of message delivery and the
- * message is removed from the outqueue. Additional delivery information
- * can be found in msg->audit: rejected messages (0x040000 (IPADRJCT)) and
- * purged messages (0x010000 (IPADPGNR)).
+ * The function is called upon completion of message delivery to remove the
+ * message from the outqueue. Additional delivery information can be found
+ * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
+ * purged messages (0x010000 (IPADPGNR)).
*
* Locking: struct hvc_iucv_private->lock
*/
* hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
* @id: hvc_iucv_table index
*
- * This function allocates a new hvc_iucv_private struct and put the
- * instance into hvc_iucv_table at index @id.
+ * This function allocates a new hvc_iucv_private structure and stores
+ * the instance in hvc_iucv_table at index @id.
* Returns 0 on success; otherwise non-zero.
*/
static int __init hvc_iucv_alloc(int id)
return -ENOMEM;
}
- /* Finally allocate hvc */
+ /* finally allocate hvc */
priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /* PAGE_SIZE */
HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
if (IS_ERR(priv->hvc)) {
return rc;
}
- /* kick khvcd thread; instead of using polling */
+ /* notify HVC thread instead of using polling */
priv->hvc->irq_requested = 1;
/* setup iucv related information */
}
/**
- * hvc_iucv_init() - Initialization of HVC backend for z/VM IUCV
+ * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
*/
static int __init hvc_iucv_init(void)
{
rc = hvc_iucv_alloc(i);
if (rc) {
pr_err("Creating a new HVC terminal device "
- "failed with error code=%d\n", rc);
+ "failed with error code=%d\n", rc);
goto out_error_hvc;
}
}
projects / openwrt / staging / blogic.git / commitdiff